KR20150017717A - Polarizing plate protective film, polarizing plate, and resistive touch panel - Google Patents

Abstract

The present invention relates to a polarizing plate protective film comprising a polarizing plate protective film formed by forming a silane coupling agent layer on one surface of a siloxane crosslinking type acrylic silicone resin film and a polarizing plate protective film formed by laminating the above protective film on the one side or both sides of the polarizing film through the silane coupling agent layer And a resistive film type touch panel using the polarizing plate.

Description

[0001] The present invention relates to a polarizing plate protective film, a polarizing plate, and a resistive touch panel,

The present invention relates to a polarizing plate protective film, a polarizing plate using the protective film, and a resistive film touch panel using the polarizing plate.

A polarizing plate is a member used for forming an image display device such as a liquid crystal display (LCD), an electroluminescent display (ELD), or a plasma display, and a polarizer (polarizing film) will be.

Conventionally, as a polarizing plate, a layer structure of a TAC film / polarizer / TAC film using triacetyl cellulose (hereinafter, "TAC") film as a protective film of a polarizer is generally used (for example, see Patent Document 1).

However, in general, the polarizing plate is usually subjected to a complicated manufacturing process in which the surface of the film is saponified to adhere the TAC film to the polarizer, and then the film is dried and then adhered to the polarizer using an aqueous polyvinyl alcohol solution as an adhesive There is a problem that a process is required. The polarizing plate using the TAC film as a protective film had a surface hardness of about H at the pencil hardness, and even when the hard coat treatment was applied to the surface, the polarizing plate had a problem that it was low at about 2H. In addition, since the TAC film has high water absorbency and moisture permeability, there has been a problem that under a high temperature and high humidity environment, it causes a short period of time, a decrease in polarization degree, a change in color, leakage of light in a quadrature Nicols state and a large dimension change of a polarizing plate.

Although attempts have been made to use, for example, polycarbonate or acrylic polymer as a protective film of a polarizer as a film other than the TAC film, it is difficult to bond the film with the polarizer, It is a phenomenon that it is not.

In recent years, a resistive film type low-reflection touch panel having a polarizing plate disposed on a surface thereof is applied as an input device for automobile navigation and the like. However, a polarizing plate change in a harsh high temperature and high humidity environment of a vehicle environment causes inconvenience to the touch panel There is a possibility of causing it.

[Patent Document 1] JP-A 2006-227604

An object of the present invention is to provide a polarizing plate protective film which does not require hard coating treatment because of its high surface hardness and which does not cause a decrease in polarization degree or a dimensional change even in an environment of high temperature and high humidity and a polarizing plate using this film, And to provide a resistive film touch panel using the same.

The present inventors have studied hard to achieve the above-mentioned object. As a result, according to the polarizing plate protective film formed by forming the silane coupling agent layer on one side of the siloxane crosslinking type acrylic silicone resin film, the polarizing plate protective film can be easily adhered to the polarizer without complicated steps, , It was found that the polarizing plate obtained by the method of the present invention hardly causes a decrease in the degree of polarization or a dimensional change of the polarizing plate even in a high temperature and high humidity environment.

In addition, when the polarizing plate is used for the surface of a polarizing plate, that is, for an LCD or a touch panel, high surface hardness can be obtained by using the polarizing plate protective film on the surface that is the outermost surface.

The present inventors have completed the present invention based on the above-described various findings and have repeatedly carried out various studies.

The present invention provides the following polarizing plate protective film, a polarizing plate using the protective film, and a resistive film touch panel using the polarizing plate.

1. A polarizer protective film comprising a siloxane crosslinked acrylic silicone resin film and a silane coupling agent layer formed on one surface thereof.

2. The polarizing plate protective film according to item 1 above, wherein the silane coupling agent is an isocyanate-based silane coupling agent.

3. A polarizing plate obtained by laminating a protective film of the above item 1 on one side or both sides of a polarizer with the silane coupling agent layer interposed therebetween.

*4. The polarizing plate according to item 3, wherein the polarizer is a polarizing film obtained by adsorbing an oxo or dichroic dye to a film made of a polyvinyl alcohol-based polymer.

5. The polarizing plate according to item 3, wherein the protective film and the polarizer are adhered using an aqueous adhesive made of a polyvinyl alcohol aqueous solution.

6. A resistive film touch panel using the polarizer according to item 3 above.

Polarizer protective film

The protective film of the polarizing plate used in the present invention is formed by forming a silane coupling agent layer on one surface of a siloxane crosslinked acrylic silicone resin film.

Siloxane  Crosslinked acrylic silicone resin

In the protective film, the resin forming the siloxane crosslinked acrylic silicone resin film is an organic-inorganic hybrid polymer composed of an acrylic resin portion and a silicone resin portion.

As the siloxane crosslinkable acrylic silicone resin film, for example, the silicone resin composition described in WO 2004/085501 A1 and the film obtained using the silicone resin composition described in JP 2004-123936 A can be used.

In particular, it is preferable to use a film obtained using the silicone resin composition described in WO 2004/085501 A1.

That is, the compound represented by the formula (1):

[Chemical Formula 1]

[RSiO _{3/2] n}

(Wherein R is an organic functional group having a (meth) acryloyl group and n is 8, 10 or 12), and polyorganosilsesquioxane having a cage structure in its structural unit is used as a main component in the silicone resin and the molecular -R ¹ -CR _² = CH ² or -CR _² = CH ² (However, R ¹ represents an alkylene group, an alkylidene group or a -OCO-, R ² represents a hydrogen or an alkyl group) And at least one unsaturated group represented by the formula

* A film obtained by using the silicone resin composition, wherein the silicone resin and the unsaturated compound capable of radical copolymerization are blended in a weight ratio of 1: 99 to 99: 1.

It is preferable that 10 to 100% by weight of the unsaturated compound capable of radical copolymerization with the silicone resin in the silicone resin composition is an alicyclic unsaturated compound represented by the following formula (2). In the formula (2), Z is a group represented by the following formula (2a) or (2b).

(2)

In the above formula (2), R 'represents a hydrogen atom, an alkyl group (particularly a lower alkyl group such as a methyl group), a phenyl group, or a (meth) acryloyl group.

The siloxane crosslinkable acrylic silicone resin film can be produced, for example, by adding a radical polymerization initiator such as a thermal polymerization initiator or a photopolymerization initiator to the silicone resin composition described in WO 2004/085501 A1, (Casting and casting) a PET film, a polyolefin film, a polypropylene film, or a polyethylene film, and curing the film by heating or light irradiation. Among these films, it is preferable to use a PET film.

When the film is prepared by heating, the curing temperature can be selected from a wide range from room temperature to around 200 캜, depending on the type of the thermal polymerization initiator and the like. When a film is prepared by light irradiation, ultraviolet rays having a wavelength of 10 to 400 nm or visible light having a wavelength of 400 to 700 nm are irradiated to obtain a film. The wavelength of light to be used is not particularly limited, but near-ultraviolet rays having a wavelength of 200 to 400 nm are particularly preferably used. Mercury lamps (output: 0.4 to 4 W / cm), high pressure mercury lamps (40 to 160 W / cm), ultra high pressure mercury lamps (173 to 435 W / cm), metal halide lamps To 160 W / cm), a pulse xenon lamp (80 to 120 W / cm), and an electroless discharge lamp (80 to 120 W / cm). Since these ultraviolet lamps are characterized by their spectral distributions, they are selected according to the type of photoinitiator used.

The siloxane crosslinked acrylic silicone resin film is obtained, for example, by pouring the above-mentioned silicone resin composition as a raw material onto a PET film continuously drawn out, using a comma coater (Comma Coater) The film was overlapped while continuously pulling out the film, and irradiated with ultraviolet rays through a transparent PET film to crosslink and cure the raw resin to form a siloxane crosslinked acrylic silicone resin film. Then, the upper and lower PET films were peeled and wound , And by winding the obtained objective film, it can be continuously and efficiently produced.

The thickness of the siloxane crosslinkable acrylic silicone resin film is not limited as long as it functions as a polarizing plate protective film. But it is preferably in the range of about 1 to 1,000 mu m, more preferably about 30 to 300 mu m.

Silane Coupling agent

In the protective film of the present invention, a silane coupling agent layer is formed on one side of the siloxane crosslinkable acrylic silicone resin film. The silane coupling agent layer formed on the surface of the protective film causes a curing reaction by moisture but does not give any chemical damage to the oxo complex or the dichroic dye contained in the polarizer by this reaction, It is possible to obtain an advantage of exerting an action of improving the adhesive force with an aqueous adhesive such as an aqueous solution.

This silane coupling agent layer can be easily formed by applying and drying a coating liquid obtained by diluting the coupling agent with an organic solvent and / or water, if necessary. Examples of the organic solvent that can be used include alcohols such as isopropyl alcohol and ethyl alcohol; And hydrocarbons such as cyclohexane. The concentration of the silane coupling agent in the coating liquid is usually about 0.1 to 100% by volume, more preferably about 1 to 5% by volume.

UV irradiation treatment, corona discharge treatment, plasma treatment, ITRO (ITRO) treatment, and the like were carried out in advance in order to improve the wettability and adhesion of the film surface of the siloxane crosslinkable acrylic silicone resin in advance of the application of the silane coupling agent , A primer treatment, a chemical treatment, or the like may be carried out. The corona discharge treatment and the UV irradiation treatment can be performed in air, nitrogen gas, rare gas or the like.

As the silane coupling agent, an isocyanate-based silane coupling agent, an amine-based silane coupling agent, or the like can be used.

Examples of the amine silane coupling agent include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (Aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene ) Propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and the like.

As the isocyanate-based silane coupling agent, those represented by the following formula (3) are preferably used.

(3)

In the general formula (3), R ³ and R ⁴ are the same or different substituted or unsubstituted monovalent hydrocarbon groups, and those having 1 to 12 carbon atoms, especially 1 to 6 carbon atoms are preferred. Examples of such monovalent hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, butyl, and hexyl; A cycloalkyl group such as a cyclohexyl group; Alkenyl groups such as a vinyl group and an aryl group; Aryl groups such as phenyl and trityl groups; And a chloromethyl group, a trifluoropropyl group, and a cyanoethyl group in which some or all of the hydrogen atoms of these groups are substituted with a halogen atom, cyano group or the like. Examples of R ³ and R ⁴ include a C _{1 -10} alkoxy-substituted C _1-10 alkyl group such as methoxymethyl group, ethoxymethyl group and methoxyethyl group, and C _{7 -20} aralkyl group such as phenylethyl group. Examples of the hydrolyzable group represented by OR ⁴ include a C _{1 -10} alkoxy group, a C _{2 -10} alkenyloxy group, a C _{6 -16} aryloxy group, a C _{1 -10} alkoxy-substituted C _{1 -10} alkoxy group, a C _{7 -17} An aralkyloxy group, and the like. R ⁵ represents an alkylene group such as a methylene group, an ethylene group or a propylene group; A divalent hydrocarbon group of 1 to 10 carbon atoms such as an allylene group such as a phenylene group, or a sulfur-substituted divalent hydrocarbon group. A is 0, 1 or 2;

Specific examples of the isocyanate-based silane coupling agents include the following ones, but the hydrolysis and condensation of the mixed silane with (R ⁴ O) ₂ SiR ³ ₂ , (R ⁴ O) ₃ SiR ₃ , Condensation product.

[Chemical Formula 4]

These silane coupling agents may be used singly or in combination of two or more. Among these coupling agents, it is particularly preferable to use an isocyanate-based silane coupling agent because it is difficult to cause a decrease in the degree of polarization and a color change even in a high temperature and high humidity environment.

The method of applying the silane coupling agent is not limited as long as it can be coated on the siloxane crosslinked acrylic silicone resin film. For example, gravure roll, wire bar, wess, dicotta, comma coater, roll coater, and Maya bar can be used.

The thickness of the application of the silane coupling agent layer is not limited to the function of the polarizing plate and may be a thickness that can be adhered to the polarizer. Usually, the thickness after drying is preferably about 2 nm to 1 mu m. The drying condition after application is preferably about room temperature to about 100 ° C for about 1 to about 10 minutes.

The protective film of the present invention can be obtained by forming a silane coupling agent layer on one surface of a siloxane crosslinkable acrylic silicone resin film.

1 is a schematic view showing a cross section of a polarizing plate protective film of the present invention. In the figure, 1 denotes a siloxane crosslinkable acrylic silicone resin film layer and 2 denotes a silane coupling agent layer.

Polarizer

The polarizing plate of the present invention is formed by laminating a protective film formed by forming a silane coupling agent layer on one side of a siloxane crosslinkable acrylic silicone resin film on one side or both sides of a polarizer through a silane coupling agent layer.

As the polarizer (polarizing film) used as the polarizing plate of the present invention, for example, a film made of a polyvinyl alcohol polymer such as polyvinyl alcohol or partially formalized polyvinyl alcohol is uniaxially oriented and then adsorbed to oxo, Which can be obtained by treating and drying under tension; It is preferable to use a film obtained by immersing a film made of a polyvinyl alcohol polymer in an aqueous solution of oxo to adsorb the oxo, and then uniaxially stretching the film in boric acid and drying under tension. Instead of oxo, a polarizing film similarly prepared using dichromatic dyes such as azo, anthraquinone, and tetrazine can also be used.

The thickness of the polarizer (polarizing film) thus obtained may be within a range that does not impair the function of the polarizer. But it is usually preferably about 5 to 100 mu m. The degree of polarization of the polarizer is preferably 95.0% or more, more preferably 99.0% or more, still more preferably 99.7% or more.

The polarizing plate of the present invention can be easily prepared usually by adhering a protective film on both surfaces of a polarizer so as to have a laminated structure of a protective film / polarizer / protective film.

As the adhesive, it is preferable to use an aqueous adhesive composed of a polyvinyl alcohol aqueous solution. The concentration of polyvinyl alcohol is usually about 0.1 to 5% by weight.

The polyvinyl alcohol constituting the adhesive is mainly composed of a resin obtainable by saponifying a vinyl acetate resin. The polyvinyl alcohol preferably has a degree of saponification of about 94% or more at a degree of polymerization of about 1,000 to 3,000 and a degree of polymerization of 1,500 to 3,000 And more preferably 98% or more of the degree of saponification. It may be a copolymer obtained by copolymerizing a small amount of another monomer such as acrylic acid, crotonic acid, itaconic acid or the like in a small amount to meet the purpose, for example, an alkyl group or an epoxy group.

The coating amount of the adhesive solution is preferably 0.01 to 10 占 퐉, more preferably 0.02 to 5 占 퐉, and still more preferably 0.05 to 3 占 퐉 in terms of the thickness after drying. If the application amount of the adhesive is too small, the adhesive force tends not to be obtained as expected, and if the application amount is too much, the cost is disadvantageous.

Next, the polarizer of the present invention can be obtained by pressing the adhesive with the polarizer in an undried or semi-dry state and drying at about room temperature to about 60 ° C for about 5 to about 24 hours.

2 is a schematic view showing a cross section of an example of a polarizing plate of the present invention. In the figure, reference numeral 1 denotes a siloxane crosslinkable acrylic silicone resin film layer, 2 denotes a silane coupling agent layer, 3 denotes an adhesive layer, and 4 denotes a polarizer (polarizing film).

The polarizing plate of the present invention can be suitably used as a polarizing plate for general resistive low-reflection touch panels. In this case, a higher surface hardness can be obtained on the surface of the polarizing plate, that is, on the surface of the topmost surface when used for the touch panel.

3 is a schematic view showing a cross section of a general resistive low reflection touch panel using a polarizing plate. In the figure, reference numeral 6 denotes a polarizing plate, 7 denotes an ITO film, 8 denotes a spacer, 9 denotes a pressure-sensitive adhesive, and 10 denotes an ITO glass.

The low reflection touch panel uses the polarizing plate on the surface of the touch panel. On the back surface, a transparent plane member having a resistive film made of a transparent electrode such as ITO is arranged at a set interval and opposed to each other. At the time of driving, the user presses an arbitrary position on the flat member with a finger or a pen, and the resistive films are brought into contact with each other at the corresponding positions to energize the resistive film. Then, from the magnitude of the resistance value from the reference position to the contact position, Is detected. Thereby, the coordinate of the contact portion on the panel is recognized and an appropriate interface function is achieved.

Although Fig. 3 shows films and glass as transparent planar members, it may be a film and a film, a glass and a film, or a film and a film in which a support such as a glass plate or a plastic plate is laminated.

The low reflection touch panel using a polarizing plate has a linear polarizing type and a circular polarizing type.

The film used as a base material for forming a resistive film with a linearly polarizing type low reflection touch panel is preferably a film obtained by coating a film of a thermoplastic resin such as an aliphatic cyclic polyolefin, a norbornene thermoplastic resin, a polyether sulfone (PES), a polycarbonate (PC) Is a film having optical isotropy.

A film used as a circular polarization type low reflection touch panel is a retardation film formed by stretching the optically isotropic film. Or an optically isotropic film may be used, and a separate phase difference film may be laminated between the polarizing plate and the electrode film. In the case of the circularly polarizing type, the retardation film is also laminated on the back surface of the glass.

The planar member on the upper side in the transparent planar member is usually about 50 to 500 mu m in thickness and is used as an upper structure of the low reflection touch panel by being adhered to the polarizing plate by a pressure sensitive adhesive having a thickness of about 10 to 50 mu m.

(1) The surface hardness of the polarizing plate of the present invention is remarkably improved. That is, by using the siloxane crosslinked acrylic silicone resin film as the protective film, the surface pencil hardness can be improved to about 4H to 8H by hard coat treatment. Therefore, it can be suitably used for a cellular phone screen or a low reflection touch panel surface requiring a high surface hardness.

(2) The polarizing plate of the present invention does not cause problems such as a decrease in the degree of polarization, a change in color, leakage of light in the orthogonal Nicole state, and dimensional change of the polarizing plate even in an environment of high temperature and high humidity. The reason why this effect can be obtained is that the siloxane crosslinked acrylic silicone resin film has a low water vapor transmission rate of usually about 14 g / m ² / day, and the dimensional change is small. Therefore, even when a poor environmental resistance such as a polarizing plate used for a liquid crystal such as a vehicle-use navigator or a polarizing plate used for a low-reflection touch panel is required, it can be suitably used.

On the other hand, in the conventional polarizing plate using a TAC protective film which is generally used, the film has an extremely high moisture permeability of about 300 g / m ² / day or so, deterioration such as a decrease in the degree of polarization under an environment of high temperature and high humidity, There is a possibility that the contrast of the liquid crystal is broken or inconveniences such as deforming the shape when used in a low reflection touch panel may occur.

(3) The polarizing plate of the present invention can be prepared by a simple method based on the ease of preparation of the protective film. That is, the protective film used in the present invention can be easily prepared by a simple method of applying a silane coupling agent to a siloxane crosslinked acrylic silicone resin film, and can be easily protected by a conventional protection that requires saponification treatment and air drying treatment Compared with TAC film, which is a film, the time can be shortened by coating with one layer, and the air drying process is eliminated, so that the operation is simple. Therefore, the polarizing plate of the present invention can be easily prepared by a simple method in which the protective film is merely adhered to the polarizer.

The surface hardness of the polarizing plate of the present invention is remarkably improved. Therefore, it can be suitably used for a cellular phone screen or a low reflection touch panel surface requiring a high surface hardness.

In addition, the polarizing plate of the present invention does not easily cause problems such as a decrease in the degree of polarization, a change in color, leakage of light in the orthogonal Nicole state, and dimensional change of the polarizing plate even in an environment of high temperature and high humidity. Therefore, even when a poor environmental resistance such as a polarizing plate used for a liquid crystal such as a vehicle-use navigator or a polarizing plate used for a low-reflection touch panel is required, it can be suitably used.

The polarizing plate of the present invention can be prepared by a simple method based on the ease of preparation of the protective film. Therefore, the polarizing plate of the present invention can be easily prepared by a simple method in which the protective film is merely adhered to the polarizer.

1 is a schematic view showing a cross section of a polarizing plate protective film of the present invention.
2 is a schematic view showing a cross section of an example of a polarizing plate of the present invention.
3 is a schematic view showing a cross section of an example of a resistive film touch panel.
4 is a schematic cross-sectional view illustrating a resistance-type touch panel application test.
DESCRIPTION OF REFERENCE NUMERALS
One… Siloxane crosslinked acrylic silicone resin film layer
2… The silane coupling agent layer
3 ... Adhesive layer
4… Polarizer
6 ... Polarizer
7 ... ITO film
8… Spacer
9 ... adhesive
10 ... ITO glass
11 ... adhesive
12 ... ITO electrode

Hereinafter, the present invention will be described in more detail with reference to Production Examples, Examples and Comparative Examples. In each example, the polarizing degree of the polarizing plate, the environmental test, the pencil hardness test, the dimensional change test and the resistance film type touch panel application test were carried out as follows.

Polarization degree of polarizer

Two polarizing plates were superimposed on each other so that their polarization axes were in the same direction, and the light transmittance was continuously measured from 400 nm to 700 nm using a spectrophotometer. The average value of the light transmittance is T ₁ . Next, two polarizing plates are superimposed so that the polarization axes thereof are orthogonal to each other, and the average value of the light transmittance measured in the same manner is T ₂ . From these values, the degree of polarization was calculated by the following equation.

Polarization degree (%) = {(T ₁ -T ₂ ) / (T ₁ + T ₂ )} ^1/2 × 100

Environmental test

The polarizing plate was allowed to stand in an atmosphere at a temperature of 80 캜 and a humidity of 90% RH for 40 hours. The polarization degree after the test was compared with the polarization degree before the test. The smaller the decrease in the degree of polarization, the better the heat and humidity resistance.

Pencil hardness test

The surface was scratched with a pressure of 1 kg using a pencil of various hardness according to the test method prescribed in JIS K 5400, and surface hardness was judged by the presence or absence of scratches. It is indicated by the pencil hardness at the time when the number of times of the scratching is less than two times by five times test. The hardness of the pencil used is 17 kinds in total of H to 9H, F, HB and B to 6B.

Dimensional change test

The polarizing plate is cut to a certain size of 60 mm in the orientation axis direction (MD direction) of the PVA polarizer and 50 mm in the direction perpendicular thereto (TD direction). Dimensions of the cut polarizing plate in the TD and MD directions are measured by a measuring instrument, and this is regarded as an initial dimension L ₁ . The dimensions after the environmental test (temperature 80 ° C, 24 hours and temperature 85 ° C, humidity 90%, 24 hours) are measured in the same manner, and the dimension after test is set to L ₂ . From these values, the dimensional change was calculated by the following formula. The polarizing plate shrinks as the value of dimensional change increases, and the polarizing plate expands as the + value increases.

Dimensional change (%) = [(L ₂ - L ₁ ) / L ₁ ] × 100

Resistive membrane  Touch panel application test

The polarizing plate was attached to a film formed on the surface of the ITO transparent electrode using an acrylic pressure-sensitive adhesive (thickness: 25 mu m), and the polarizer was fixed at 70 mm in the orientation axis direction (MD direction) And the upper structure of the resistance film type low reflection touch panel is obtained. The obtained sample is subjected to environmental testing (temperature 85 ° C, humidity 90%, 120 hours), and the size (mm) of the warped state is measured in the figure as shown in FIG. 4 is a schematic cross-sectional view illustrating a resistance-type touch panel application test. In the figure, reference numeral 6 denotes a polarizing plate, 7 denotes an ITO film, 11 denotes a pressure-sensitive adhesive, and 12 denotes an electrode. The amount of warpage was measured at four angles of the sample, and the average value was defined as a warped amount. When the amount of warping is small, it is difficult to cause inconvenience when used in an actual touch panel structure, and when the amount of warping is large, inconvenience is likely to occur.

Example 1: Preparation of protective film

(Casting) a silicone resin composition (product number " 2015 ", product of Nippon Steel Chemical Co., Ltd.) described in WO 2004/085501 A1 was cast on a PET film, Wavelength: 320 nm, irradiation time: 3 seconds) to prepare a siloxane crosslinked acrylic silicone resin film having a thickness of 200 mu m. Subsequently, both surfaces of the obtained film were subjected to corona discharge treatment in air at a treatment intensity of 300 W / m ²占 to obtain a water contact angle of 37 占 (23 占 폚).

Next, on one surface of the surface-treated siloxane crosslinked acrylic silicone resin film, an isocyanate-based silane coupling agent (trade name: KBE-9007, manufactured by Shin-Etsu Chemical Industry Co., Triethoxysilane) in a cyclohexane solution was applied using a wire bar so that the thickness after drying was 1.0 占 퐉, left in an oven at 100 占 폚 for 10 minutes, and dried.

To obtain a polarizing plate protective film of the present invention having a silane coupling agent layer formed on one side of a siloxane crosslinkable acrylic silicone resin film.

Preparation Example 1 Preparation of Polarizers

An aqueous solution consisting of 5,000 parts by weight of water, 35 parts by weight of oxo, and 525 parts by weight of potassium iodide was coated on a polyvinyl alcohol film (trade name: Kurarabinylon film VF-9 X75R, manufactured by Kuraray Co., Ltd., For 5 minutes to adsorb the oxo. Then, the film was uniaxially stretched in the longitudinal direction at a ratio of 4.4 times in a 4 wt% boric acid aqueous solution at 45 캜, and then dried while being stretched to obtain a polarizer (polarizing film) having a thickness of 17 탆.

Example 2: Preparation of a polarizing plate

An aqueous 1.5 wt% solution of polyvinyl alcohol having an average degree of polymerization of 1,800 and a degree of saponification of 99% was used as an adhesive. The adhesive agent was applied on both sides of the polarizing film obtained in Production Example 1 so that the thickness after drying was 1 占 퐉 and the adhesive was dried in an undried state and a silane couple of the polarizing plate protective film obtained in Example 1 And a nucleus initialization program between a rubber roll / metal roll (rubber roll diameter of 200 mm, metal roll diameter of 350 mm, line pressure of 10 kg / cm) It was allowed to stand in an oven at 40 DEG C for 24 hours and then dried.

Thus, a polarizing plate composed of a protective film / polarizing film / protective film layer structure was obtained.

The degree of polarization of the obtained polarizing plate was 99.8%, and the pencil hardness of the surface of the protective film was 4H. It was also found that the degree of polarization after the environmental test (temperature 80 ° C, humidity 90%, 40 hours) was 99.8%, there was no decrease from the degree of polarization before testing, and the resistance to humidity and humidity was excellent.

Example 3

The dimensional change of the polarizing plate obtained in Example 2 under an environment of high temperature, high temperature and high humidity was measured. The dimensional change at high temperature of 80 DEG C for 24 hours was -0.23% in the MD direction and -0.20% in the TD direction. The dimensional changes at high temperature 85 ° C and high humidity 90% and 24 hours were -0.10% in the MD direction and 0.15% in the TD direction. Thus, there was almost no dimensional change.

Next, a resistance film type touch panel application test was carried out. An ITO transparent electrode (thickness: 30 nm, surface resistance: 250? /?) Was formed on the surface of the siloxane crosslinked acrylic silicone resin film (thickness: 200 m) prepared in Example 1 by sputtering . The warped amount of the upper structure is 0.6 mm after the environmental test at a temperature of 85 캜 and a humidity of 90% for 120 hours. The polarized plate does not cause a bending state, and a polarizing plate can be used to construct a resistive film low reflective touch panel having high environmental durability .

Comparative Example 1

Same as Example 2 except that a TAC film (trade name "TDY80UL", manufactured by Fuji Photo Film Co., Ltd.) was adhered to both surfaces of the polarizing film in place of the polarizing plate protective film obtained in Example 1 in Example 2 To obtain a comparative polarizing plate. The degree of polarization of the obtained polarizing plate was 99.8%, and the surface pencil hardness was H. The degree of polarization after the environmental test (temperature 80 ° C, humidity 90%, 40 hours) was 94.1%, and it was found that the degree of polarization greatly decreased before and after the test and was inferior to the resistance to humidity and humidity.

Comparative Example 2

In Comparative Example 1, a protective film for a polarizing plate for comparison was obtained without applying a silane coupling agent to a siloxane crosslinked acrylic silicone resin film which had been subjected to corona discharge treatment at a water contact angle of 37 占 (23 占 폚).

Subsequently, in the same manner as in Example 2, a 1.5 wt% aqueous solution of polyvinyl alcohol having an average polymerization degree of 1,800 and a degree of saponification of 99% as an adhesive was applied to both surfaces of a polarizer (polarizing film) so that the thickness of the adhesive layer after drying was 1 μm Although the adhesive was attempted to adhere to the protective film in an undried state, it could not be adhered and a polarizing plate could not be obtained.

Comparative Example 3

A dimensional change of a commercially available polarizing plate (manufactured by Fora Techno Co., Ltd., trade name " SKN-18243 TL ") using a TAC film as a protective film under an environment of high temperature or high temperature and high humidity was measured. The dimensional change at high temperature of 80 占 폚 for 24 hours was -0.61% in the MD direction and -0.34% in the TD direction. The dimensional changes at high temperature 85 ℃, high humidity 90% and 24 hours were -2.44% in MD direction and -1.27% in TD direction. Thus, the dimensional change became a very large value.

Next, a resistance film type touch panel application test was carried out. The same film as that used in Example 3 was used as the film having the ITO transparent electrode formed on its surface. The warped amount of the superstructure was a temperature of 85 ° C, a humidity of 90%, an environmental test of 13.3 mm after 120 hours of environmental testing, and a large warped state. Therefore, it was found that, in a harsh environment, the polarizing plate of Example 2 is used as compared with the polarizing plate of Comparative Example 3, and a touch panel with high durability can be constructed.

Claims (1)

A polarizing plate protective film comprising a siloxane crosslinking acrylic silicone resin film and a silane coupling agent layer formed on one side thereof.

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